Introducing the OffDomainInclusionDetector to analyze resource requests for suspicious activity.

content/public/common/resource_type.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_PUBLIC_COMMON_RESOURCE_TYPE_H_
 #define CONTENT_PUBLIC_COMMON_RESOURCE_TYPE_H_
 
 #include "content/common/content_export.h"
 
 namespace content {
 
-// Used in histograms, so please add new types at the end, and rename unused
-// entries to RESOURCETYPE_UNUSED_0, etc...
+// Used in histograms, explicitly assign each type and do not re-use old values.
 enum ResourceType {
-  RESOURCE_TYPE_MAIN_FRAME = 0,  // top level page
-  RESOURCE_TYPE_SUB_FRAME,       // frame or iframe
-  RESOURCE_TYPE_STYLESHEET,      // a CSS stylesheet
-  RESOURCE_TYPE_SCRIPT,          // an external script
-  RESOURCE_TYPE_IMAGE,           // an image (jpg/gif/png/etc)
-  RESOURCE_TYPE_FONT_RESOURCE,   // a font
-  RESOURCE_TYPE_SUB_RESOURCE,    // an "other" subresource.
-  RESOURCE_TYPE_OBJECT,          // an object (or embed) tag for a plugin,
-                                 // or a resource that a plugin requested.
-  RESOURCE_TYPE_MEDIA,           // a media resource.
-  RESOURCE_TYPE_WORKER,          // the main resource of a dedicated worker.
-  RESOURCE_TYPE_SHARED_WORKER,   // the main resource of a shared worker.
-  RESOURCE_TYPE_PREFETCH,        // an explicitly requested prefetch
-  RESOURCE_TYPE_FAVICON,         // a favicon
-  RESOURCE_TYPE_XHR,             // a XMLHttpRequest
-  RESOURCE_TYPE_PING,            // a ping request for <a ping>
-  RESOURCE_TYPE_SERVICE_WORKER,  // the main resource of a service worker.
+  RESOURCE_TYPE_MAIN_FRAME = 0,       // top level page
+  RESOURCE_TYPE_SUB_FRAME = 1,        // frame or iframe
+  RESOURCE_TYPE_STYLESHEET = 2,       // a CSS stylesheet
+  RESOURCE_TYPE_SCRIPT = 3,           // an external script
+  RESOURCE_TYPE_IMAGE = 4,            // an image (jpg/gif/png/etc)
+  RESOURCE_TYPE_FONT_RESOURCE = 5,    // a font
+  RESOURCE_TYPE_SUB_RESOURCE = 6,     // an "other" subresource.
+  RESOURCE_TYPE_OBJECT = 7,           // an object (or embed) tag for a plugin,
+                                      // or a resource that a plugin requested.
+  RESOURCE_TYPE_MEDIA = 8,            // a media resource.
+  RESOURCE_TYPE_WORKER = 9,           // the main resource of a dedicated
+                                      // worker.
+  RESOURCE_TYPE_SHARED_WORKER = 10,   // the main resource of a shared worker.
+  RESOURCE_TYPE_PREFETCH = 11,        // an explicitly requested prefetch
+  RESOURCE_TYPE_FAVICON = 12,         // a favicon
+  RESOURCE_TYPE_XHR = 13,             // a XMLHttpRequest
+  RESOURCE_TYPE_PING = 14,            // a ping request for <a ping>
+  RESOURCE_TYPE_SERVICE_WORKER = 15,  // the main resource of a service worker.
   RESOURCE_TYPE_LAST_TYPE
 };
 
 CONTENT_EXPORT bool IsResourceTypeFrame(ResourceType type);
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_COMMON_RESOURCE_TYPE_H_